The present invention relates to a casing for a magnetic tape cassette, and more particularly to a casing for a magnetic tape cassette which is conveniently used to record a digital signal, such as a PCM signal for example.
PCM recording and reproducing apparatus have recently been proposed which are adapted to convert an analog signal such as an acoustic signal or the like into a digital signal such as a PCM signal for example, and then record the digital signal on a magnetic tape element for reproducing the same. One such conventional PCM recording and reproducing apparatus is generally constructed to utilize a rotary head for carrying out recording on a magnetic tape element at relatively high density. More particularly, the recording and reproducing apparatus is adapted to draw out a magnetic tape element from a casing and wind up the same on a rotating drum which is provided with the rotary head, during the recording or reproducing operation.
When a fingerprint, dust, or the like adheres to a magnetic tape element, a drop out is likely to be caused or occur in a reproducing signal of a magnetic tape cassette used in such a PCM recording and reproducing apparatus. In order to avoid such a problem, it is necessary to keep the magnetic tape element in a casing as much as possible, in order to protect the same. Also, in order to assure smooth drawing-out of the tape element from the casing during recording or reproducing, it is necessary to provide the casing with a space through which guide means of the apparatus are able to be inserted into the cassette casing.
In order to meet such requirements, a casing for a magnetic tape cassette has been proposed which is generally constructed in a manner such as illustrated in FIGS. 1 and 2. More particularly, the casing generally designated by reference numeral 100 includes an upper casing member 102 and a lower casing member 104 joined together to define a space therein for housing a magnetic tape element. The casing also includes a slider 106 arranged outside of the lower casing member 104 as illustrated. The slider 106 is formed with a sufficient shape to cover a bottom and a part of each of both sides of the lower casing member 104, and is slidably received at each of both sides thereof in a recess 108 in the lower casing member 104, so as to be flush with an outer surface of the upper cover member 102.
The slider 106 is adapted to be slidably reciprocated along the outer surface of the lower casing member 104 in the recess 108 in a direction of the casing sides. The casing 100 is also provided at a front wall thereof with an opening which is selectively closed by a front cover 110. The front cover 110 is pivotally mounted at a front portion of the casing, so that the front cover 110 may be actuated due to sliding movement of the slider 106, to selectively cover the front opening of the casing 100.
When the casing 100 constructed as described above as illustrated in FIGS. 1 and 2 and in which a magnetic tape element has been arranged to form a magnetic tape cassette, is inserted in a recording and reproducing apparatus, the slider 106 is moved in a rearward direction of the casing 100 to pivotally move the front cover 110 to expose the front opening of the cassette casing. Thus, the magnetic tape element may be exposed through the front opening of the casing 100. During non-use of the magnetic tape cassette, the slider 106 is positioned at a forward position to cause the front cover 110 to close or cover the front opening of the casing 100, to sealingly maintain the magnetic tape element within the casing 100.
When the casing 100 is to be inserted in the recording and reproducing apparatus, an operator generally grasps the recess 108 or a portion of the casing 100 adjacent thereto. This hinders smooth sliding of the slider 106, leading to failure of smooth insertion of the magnetic tape cassette in the apparatus. Also, when the magnetic tape cassette is removed from the recording and reproducing apparatus, the slider 106 is left at its retracted or backward position, depending upon the apparatus, so that it is necessary for an operator to manually move the slider to its forward position to close the opening of the casing.
This is generally carried out in a manner by the operator grasping a portion of the casing 100 at which the retracted slider is positioned, to remove the magnetic tape cassette from the apparatus. Accordingly, the tape is removed while leaving the slider at the retracted or backward position, so that the front opening of the casing 100 is left open. This causes adhesion of dust, fingerprinting, or the like on the magnetic tape element, resulting in a drop out in a signal stored on the tape element.
Accordingly, it would be highly desirable to develop a casing for magnetic tape cassette which is capable of constantly assuring smooth actuation of a slider and permitting an operator to carry out charging and withdrawing of the magnetic tape cassette with respect to recording and reproducing apparatus without directly contacting the slider.